This invention relates to a quick disconnect coupling with locked valving and, more particularly, to the female half of the coupling.
The invention finds utility in connecting and disconnecting hydraulic hoses, generally used on agricultural equipment. The female half is mounted on the tractor and is connected to the tractor hydraulic system. The male half is the implement hose and can be a commercially available male half.
Couplings used on agriculture equipment have a unique requirement in addition to normal connecting and disconnecting of the hydraulic hoses. It is quite common for the male half (implement half) to have trapped hydraulic pressure in the hose. Conventional hydraulic couplings will not connect with trapped pressure in the hose. However, agricultural couplings such as those illustrated in U.S. Pat. No. 3,163,178 will connect against trapped pressure in the male half--this being accomplished by allowing valve overtravel in the female. However, the problem with the above-mentioned design (and similar designs such as those found in U.S. Pat. Nos. 3,477,468, 3,482,602 and 4,098,292) is that the valves are held in the open position by springs. Thus, under high fluid flow conditions (male to female direction) the fluid force or pressure drop exceeds the spring force. When that happens, the valve shift and the coupling closes off the flow. When this condition happens (flow being stopped) the implement may be damaged and the operator must reset the coupling. This disadvantageous operating is avoided by the instant invention which prevents the problem by locking the valve open during high flow conditions.
This is achieved in the illustrated embodiment of the invention through the provision of a supplementary sleeve for the female valve element which blocks radial movement of positioning balls interposed between the valve element and the valve guide. In normal operation, these balls are free to move radially outward and when the female half valve is closed are in a radially outward position. Through the use of the above-mentioned sleeve, the turbulents of the reverse flow moves the sleeve into blocking relation and thus prevents closing of the female half valve until the reverse flow condition ceases or is reduced to a predetermined, acceptable value.
Other objects and advantages of the invention may be seen in the details of the ensuing description.